[Comparison of four human growth hormone (hGH) immunoassay kits and analysis of recognition of circulating forms].
Three immunoradiometric assay (IRMA) kits (Pharmacia, bioMérieux and Cis-ELISA) and one competitive radioimmunoassay (RIA) kit (Cis-SB) designed for routine hGH quantitation were compared. Reproducibility was better with the IRMAs than with the RIA, especially when hGH levels were low (less than 3 mUI/l). This substantial advantage was responsible for a decrease in the qualitative detection threshold from 1.22 mUI/l for the RIA to approximately 0.08 mUI/l for the IRMAs. Analysis of accuracy showed that the Cis-ELSA kit overestimated recovery of added hGH (1st IRP 66/217) and demonstrated a marked influence of matrix effects with Cis-ELSA and Cis-SB. Pharmacia and bioMérieux kits were more accurate and showed less sensitivity to matrix effects. hGH concentrations obtained with the four kits were determined in 113 normal or abnormal sera. Despite the above-mentioned differences in accuracy, the three IRMAs yielded comparable results. Concentrations measured using the RIA were higher than those obtained with the other kits. Two sera were submitted to gel filtration chromatography. hGH assays in the fractions obtained showed that the immunologic systems used in the kits display different levels of immunoreactivity towards the circulating oligomeric and dimeric forms of hGH that they recognize. These data suggest that normal reference values should be established for each kit.
Gervasi
G
G
Fondation de Recherche en Hormonologie, Fresnes, France.
Samy
M
M
Scholler
R
R
D006130:Growth Disorders / Q000097:blood; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D015592:Immunoradiometric Assay / Q000295:instrumentation* / Q000379:methods; D011863:Radioimmunoassay / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results
D013006:Growth Hormone
Comparaison de quatre trousses de dosage de l'hormone de croissance humaine (hGH) et analyse de la reconnaissance des formes circulantes.